thats really what i'm afraid of

 

you know i have also had some friends come over that are really good with cars and they cant really figure out what the noise is. they keep leaning toward the valves though

 

Like I said though, wait for some other opinions. Just how the knock is. Does it kinda go away like after you rev it and the rpms are going back down? It sounds like it goes away on the downward rpms and then comes back when its left to idle or when you give it gas. If it was the valvetrain, it would be more consistent.

 

you can hardly hear it at idle but when it revs up the noise gets louder. if it was a rod wouldnt it have low compression?

 

you do have that 160 in there. My first engine still had plenty of power when it had a bent rod and was knocking like crazy. My second one only has bad compression because of the rings and the scratches in the cylinder walls that I thought werent that bad but actually were, but it too also has rod knock. Hopefully my third will not be the same experience. Here is a great example of rod knock and this seems to be what yours sounds like to me.
http://www.youtube.com/watch?v=M1sxt...eature=related

 

Wow just got a chance to listen. Man doesnt sound good I would have to put my money on rod knock my friend, sucks I know . I pulled a toyota engine that had that exact sound and turned out to be one of the rod journals were shot causing the rod to have play where it connects to the crank causing to to knock loud like that when revving up. When you let off the gas the pistons are not pushing the crank and so the noise will go away while rpms drop then start again when the computer brings the car to idle.I would bet the cylinder with 160 is the bad one for sure, the piston is coming up ever so slightly short of TDC as the others causing the lower comp. I would suggest finding a replacement motor BEFORE that one goes if this is your dd. Plus that way you will have more usuable parts off this motor than after it blows. This happens sometimes. The 4 runner I pulled that motor out of did the same thing just one day started doing that. Best of luck if you decide to look for another motor I will be happy to help in your search.

 

You think he already toasted his crankshaft or do you think he might be able to get away with just replacing the bearings? Im just curious cause this is one of those things Im not super knowledgable about yet and wanna learn more about. I can diagnose the sound easier than I can a solution for this specific problem. Obviously the best path would be to get another motor at this point, but is it possible to save this motor with just a new rod bearing or would he have to do a full bottom end rebuild now on this block? And to jimmhuth, are you a mechanically inclined person? Just curious.

 

The longer he drives like that the more likely he can fry the crank, The only way to know for sure is to pull out the motor and wiggle each rod to find the bad one then separate it where it connects to the crank. There should be a mirror finish on both the rod and crank surfaces. There is whats called plastic gauge used to measure the clearance of the rod to the crank, you basically take a piece of this and lay it width wise between the crank surface and the rod bearing then tighten the cap to factory torque spec and the plastic gauge will squish and flatten out, you take the cap off and measure how much the strip has flattened out and compare that to the standard value, make sure you DO NOT move the crank or rod at all or else the plastic gauge will smear and the reading is useless. You can get oversized bearings to help compensate for bigger clearances. In the case of the 4 runner, the gauge didnt even squish!!! I had to swap in another motor.

 

well my dad just listened to the video as well and he thinks its rod knock. i found a motor on ebay but i dont know how good it is. the guy doesnt know the mileage. i can put the motor in myself and to buy it and have it shipped im looking at about $600

 

Yeah that soound is exactly what is happening with my Sisters car, it sounds like a knock, and it gets faster as the engine revs higher in the RPM Band. Anything that can be done for that? Will the "SeaFoam" help that sound go away? or is the motor pretty much done?

 

Seafoam will do nothing for rod knock check post #23

 

That motor looks pretty good to be honest but you can only tell so much then go on faith when buying a motor you cant visually inspect except for photos

 

well so far i'm not having any luck on finding a motor. i guess i'm gonna drop the motor and check it out. if anyone knows of a place to find a motor please let me know.

 

car-part.com is a collection of junkyards across america. Great place to get stuff for cheap. In my experience, dont buy a motor on faith. My last block was bought on faith and now Im out quite a bit of money. Have to save up 400 to get yet another motor. Junkyards however often times guarantee a perfectly running motor for like 6 months or so. Make sure you really really ask before they buy. I got screwed on my block I bought due to some miscommunication. Now Im buying a motor from a yard that compression tests, makes sure it starts, etc before the customer buys and has a 90 day warranty to boot. Im sorry thats whats going on man.

 

Damn, so the motor will be toast soon then? That sucks. So no way to fix it when it starts making this noise? would it be cheaper/ easier to get another motor then to fix the problem motor?